Vulnerability Monitor

The vendors, products, and vulnerabilities you care about

CVE-2021-20134


Quagga Services on D-Link DIR-2640 less than or equal to version 1.11B02 are affected by an absolute path traversal vulnerability that allows a remote, authenticated attacker to set an arbitrary file on the router's filesystem as the log file used by either Quagga service (zebra or ripd). Subsequent log messages will be appended to the file, prefixed by a timestamp and some logging metadata. Remote code execution can be achieved by using this vulnerability to append to a shell script on the router's filesystem, and then awaiting or triggering the execution of that script. A remote, unauthenticated root shell can easily be obtained on the device in this fashion.


Security Impact Summary

This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 8.4, indicating it requires adjacent network access with relatively low complexity without requiring user interaction . The vulnerability impacts confidentiality (data exposure), integrity (unauthorized modifications), and availability (service disruption) for affected systems. Impacting 2 products from dlink, from dlink organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.


Published

2021-12-30T22:15:08.460

Last Modified

2024-11-21T05:45:59.307

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 8.4 (HIGH)

CVSSv2 Vector

AV:A/AC:M/Au:S/C:C/I:C/A:C

  • Access Vector: ADJACENT_NETWORK
  • Access Complexity: MEDIUM
  • Authentication: SINGLE
  • Confidentiality Impact: COMPLETE
  • Integrity Impact: COMPLETE
  • Availability Impact: COMPLETE
Exploitability Score

4.4

Impact Score

10.0

Weaknesses
  • Type: Primary
    CWE-22

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Operating System dlink dir-2640-us_firmware ≤ 1.11b02 Yes
Hardware dlink dir-2640-us - No

References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For dlink's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.